Scientists at Bell Labs have built a prototype camera that uses no lens and a single-pixel sensor. This idea is based around a grid of small apertures that each direct light rays from different parts of the scene to the sensor, and can be opened and closed independently. The sensor makes a series of measurements with different combinations of open apertures, and uses this data to reconstruct the scene in front of the camera. No lens to focus the resultant image means infinite depth of field and low cost. Click through for more details and a link to the original research.
News: Digital Photography Review (dpreview.com)